Search found 54 matches

by Reina Robles 1H
Tue Jan 21, 2020 12:32 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6B. 3
Replies: 2
Views: 13

Re: 6B. 3

I have the solutions manual and can also confirm that it's correct!
by Reina Robles 1H
Mon Jan 20, 2020 11:43 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6A.23
Replies: 3
Views: 12

Re: 6A.23

You don't need K nor the ICE table because Ba(OH)2 is a strong base and thus will be 100% dissociated in water. This means you can assume the equilibrium concentration of the reaction will be: [Ba2+]final = [Ba(OH)2]initial = 0.025M and [OH-]final = 2*[Ba2+]final = 0.05M Remember that these conclus...
by Reina Robles 1H
Mon Jan 20, 2020 11:22 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6A.23
Replies: 3
Views: 12

6A.23

"6A.23 Calculate the molar concentration of Ba(OH)2(aq) and the molar concentrations of Ba21, OH2, and H3O1 in an aqueous solution that contains 0.43 g of Ba(OH)2 in 0.100 L of solution."

Are we supposed to use the ice box method to solve this? K wasn't given.

Thanks!
by Reina Robles 1H
Sun Jan 12, 2020 2:01 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework 5G.1 Help
Replies: 3
Views: 17

Homework 5G.1 Help

5G.1 asks to "State whether the following statements are true or false. If false, explain why." For Part D of the question, it says "If one starts with higher concentrations of reactants, the equilibrium concentrations of the products will be larger." Why is that marked as true w...
by Reina Robles 1H
Sun Dec 08, 2019 9:46 am
Forum: Student Social/Study Group
Topic: Final Jitters
Replies: 95
Views: 19712

Re: Final Jitters

Test anxiety is a big issue for me and I'd like to thank everyone who gave tips! Here are some of mine (sorry for any repeats): 1. Exercise! Or at least, get moving. I can get incredibly tense while studying, and working out helps relieve that. Keeping your body healthy in general is also helpful in...
by Reina Robles 1H
Sun Dec 08, 2019 9:37 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Hydrogen
Replies: 3
Views: 28

Re: Hydrogen

If you mean hydrogen bonding, then it's where nitrogen, oxygen, and fluorine atoms with a lone pair are bonding sites (each lone pair is one bonding site). Hydrogen atoms attached to a nitrogen, oxygen, or fluorine are also bonding sites.

I hope this helps!
by Reina Robles 1H
Sun Dec 08, 2019 9:35 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: LDF
Replies: 4
Views: 29

Re: LDF

Yes, all molecules have LDF. Induced-dipole dipole occurs between a polar molecule and a non-polar molecule.

I hope this helps!
by Reina Robles 1H
Sun Dec 08, 2019 9:33 am
Forum: Lewis Structures
Topic: hydrogen bonding
Replies: 2
Views: 22

Re: hydrogen bonding

Nitrogen, oxygen, and fluorine atoms with a lone pair are bonding sites (each lone pair is one bonding site). Hydrogen atoms attached to a nitrogen, oxygen, or fluorine are also bonding sites.

I hope this helps!
by Reina Robles 1H
Sun Dec 08, 2019 9:32 am
Forum: Dipole Moments
Topic: test 2 #6
Replies: 2
Views: 24

Re: test 2 #6

Unless all the atoms are the same, tetrahedrals are always polar. CH2F2 looks flat on paper, but its 3D structure shows that it's not.

I hope this helps!
by Reina Robles 1H
Sun Dec 08, 2019 9:29 am
Forum: Naming
Topic: Naming
Replies: 7
Views: 40

Re: Naming

You use those when the ligand already contains a prefix (for example, (en)), is a polydentate, or it starts with a vowel.

I hope this helps!
by Reina Robles 1H
Sun Dec 08, 2019 9:26 am
Forum: Administrative Questions and Class Announcements
Topic: Accidentally posting in wrong class
Replies: 1
Views: 37

Re: Accidentally posting in wrong class

It's probably simpler to delete the old post and repost it here.
by Reina Robles 1H
Sun Dec 08, 2019 9:26 am
Forum: Administrative Questions and Class Announcements
Topic: Chem comm troubleshooting
Replies: 1
Views: 21

Re: Chem comm troubleshooting

Not that I know of, but it might be better to not make posts back to back.
by Reina Robles 1H
Sun Dec 08, 2019 9:25 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: boiling point
Replies: 8
Views: 39

Re: boiling point

Substances with higher boiling points will have stronger intermolecular interactions. Conversely, substances with lower boiling points will have weaker intermolecular interactions.

I hope this helps!
by Reina Robles 1H
Sun Dec 08, 2019 9:24 am
Forum: Administrative Questions and Class Announcements
Topic: Chem Comm access
Replies: 1
Views: 28

Re: Chem Comm access

I believe that you can still look at posts (since you don't have to login for that) but you can't reply or make your own unless you're going to have Dr. Lavelle for Chem 14B. In that case, you will be able to post.
by Reina Robles 1H
Sun Dec 08, 2019 9:21 am
Forum: Naming
Topic: Amine vs Ammine?
Replies: 3
Views: 49

Re: Amine vs Ammine?

Are you talking about ammine for the neutral lignad: NH3 and about their spelling? If so, I was told in one of my plf's that the spelling matters in regards to points so when naming coordination compounds make sure you write ammine with double m's! There is a difference between an amine and an ammi...
by Reina Robles 1H
Sun Dec 08, 2019 9:20 am
Forum: Naming
Topic: Any Givens During the Final?
Replies: 4
Views: 70

Re: Any Givens During the Final?

Thank you both! I am pretty sure the only givens are those we have seen on the midterm and tests. You may be able to ask about abbreviations as long as they are not on the periodic table/have been explained in class. It would be best to memorize ion charges, but worst case you can calculate the form...
by Reina Robles 1H
Sun Dec 08, 2019 9:19 am
Forum: Naming
Topic: Polydentate Ligands
Replies: 3
Views: 42

Re: Polydentate Ligands

Thank you both!
by Reina Robles 1H
Sun Dec 08, 2019 9:18 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentates
Replies: 9
Views: 63

Re: Polydentates

A ligand is polydentate if when we draw the lewis structure there is more than one bonding site in the form of lone pairs present on separate atoms in the compound. Fro the textbook, the main ones we have to know are en which is bidentate, bien which is tridentate, oxalate which is bidentate, and e...
by Reina Robles 1H
Sun Dec 08, 2019 9:17 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate
Replies: 3
Views: 31

Re: Polydentate

Polydentate ligands have more than one lone pair that it can donate. They are also usually in the structure of atom with a lone pair — space atom — space atom — atom with a lone pair.
by Reina Robles 1H
Sun Dec 08, 2019 9:07 am
Forum: Sigma & Pi Bonds
Topic: Hybridization of Pi Bonds
Replies: 1
Views: 28

Hybridization of Pi Bonds

How do you write the hybridization of pi bonds?
by Reina Robles 1H
Tue Dec 03, 2019 10:11 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentates
Replies: 9
Views: 63

Polydentates

How do I know if a ligand is polydentate? Thanks!
by Reina Robles 1H
Fri Nov 29, 2019 7:45 pm
Forum: Naming
Topic: Polydentate Ligands
Replies: 3
Views: 42

Polydentate Ligands

So I know polydentate ligands have multiple sites where they can bond to the same transition metal, but how do you know that it can do that? Thanks.
by Reina Robles 1H
Fri Nov 29, 2019 5:11 pm
Forum: Naming
Topic: Any Givens During the Final?
Replies: 4
Views: 70

Any Givens During the Final?

During the final, will we be given any information for naming coordinate compounds? (ex: what abbreviations would mean, ion charges, etc.)
by Reina Robles 1H
Fri Nov 29, 2019 4:44 pm
Forum: Naming
Topic: Amine vs Ammine?
Replies: 3
Views: 49

Amine vs Ammine?

Is there a difference between amine and ammine?
by Reina Robles 1H
Wed Nov 27, 2019 1:02 pm
Forum: Lewis Acids & Bases
Topic: What is the correct definition of a base?
Replies: 5
Views: 26

Re: What is the correct definition of a base?

A base and a Lewis base are the same thing. Lewis base just states how Lewis describes bases (donating an electron).
by Reina Robles 1H
Wed Nov 27, 2019 12:59 pm
Forum: Bronsted Acids & Bases
Topic: Acids vs Bases
Replies: 5
Views: 26

Re: Acids vs Bases

Acids have a pH lower than 7, and they produce hydronium (H3O+) when they react with water. The Lewis definition of an acid states that it accepts an electron; the Bronsted definition states that it donates a proton. Bases have a pH higher than 7, and they produce hydroxide (OH-) when they react wit...
by Reina Robles 1H
Tue Nov 26, 2019 9:13 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity and dipole moments
Replies: 8
Views: 43

Re: Polarity and dipole moments

The dipole moments cancel out when they're facing in opposite directions. If there's a diagonal dipole, I like to break them up into the two directions it's made of (up-right, down-right, etc.) and then check if any of the other dipoles cancel it out.

I hope this helps!
by Reina Robles 1H
Tue Nov 26, 2019 10:21 am
Forum: Lewis Acids & Bases
Topic: Electron acceptor / donor
Replies: 2
Views: 21

Re: Electron acceptor / donor

Normally, electron acceptors (Lewis acids) are positively charged, and electron donors (Lewis bases) are negatively charged (this may not be the case all the time). For me, drawing the Lewis structure helps determine which species has lone pairs of electrons, which helps to determine the Lewis base...
by Reina Robles 1H
Tue Nov 26, 2019 10:19 am
Forum: Dipole Moments
Topic: Intermolecular force
Replies: 5
Views: 35

Re: Intermolecular force

Yes, if the intermolecular forces between two molecules is stronger, it will be harder to break the bonds between them. The strengths of the different types of intermolecular forces in increasing order are as follows: induced dipole-induced dipole (London forces) < dipole-dipole < ion-dipole < ion-...
by Reina Robles 1H
Tue Nov 26, 2019 10:09 am
Forum: Lewis Acids & Bases
Topic: Electron acceptor / donor
Replies: 2
Views: 21

Electron acceptor / donor

So I know Lewis acids are electron acceptors, and Lewis bases are electron donors. But how do you know whether a molecule accepts or donates an electron?
by Reina Robles 1H
Tue Nov 26, 2019 10:00 am
Forum: Dipole Moments
Topic: Intermolecular force
Replies: 5
Views: 35

Re: Intermolecular force

I believe so. Just as a side note though, the molecules aren’t bonded to each other like in a covalent or ionic bond. They’re interacting with each other/strongly attracted to each other.

I hope this helps!
by Reina Robles 1H
Tue Nov 26, 2019 9:06 am
Forum: Sigma & Pi Bonds
Topic: Promotion
Replies: 5
Views: 40

Re: Promotion

Yep, promotion means that an electron goes to a higher energy orbital. However, the orbital must be empty. So while carbon can promote an electron, nitrogen can’t (none of its p orbitals are empty).

I hope this helps!
by Reina Robles 1H
Tue Nov 26, 2019 9:02 am
Forum: Naming
Topic: -ate ending
Replies: 8
Views: 47

Re: -ate ending

-ate is for negatively charged complexes. Usually complexes are neutral or positively charged, so -ate is supposed to be a red flag/signifier.
by Reina Robles 1H
Wed Nov 20, 2019 1:33 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles in Square Pyramidal and T-Shaped
Replies: 4
Views: 44

Bond Angles in Square Pyramidal and T-Shaped

Hi, I'm a little confused. Are all the bond angles in square pyramidal (AX5E) 90 degrees? What about the bond angle between the two equatorial atoms? And doesn't the lone pair also affect the angle? And with t-shaped (AX3E2, AX3E3), are the bond angles 120 and 90 degrees even though there are lone p...
by Reina Robles 1H
Tue Nov 19, 2019 3:30 pm
Forum: Administrative Questions and Class Announcements
Topic: CHEM 14A Section 4B/1H VSEPR Additional Resources
Replies: 2
Views: 90

Re: CHEM 14A Section 4B/1H VSEPR Additional Resources

Hi Tony! The link didn't work when I tried it, but I did use it to find this one: https://chem.libretexts.org/Bookshelves/General_Chemistry/Map%3A_A_Molecular_Approach_(Tro)/10%3A_Chemical_Bonding_II%3A_Molecular_Shapes%2C_Valance_Bond_Theory%2C_and_Molecular_Orbital_Theory/10.3%3A_VSPER_Theory%3A_T...
by Reina Robles 1H
Sun Nov 03, 2019 3:04 pm
Forum: Octet Exceptions
Topic: Max Expanded Octets
Replies: 2
Views: 20

Re: Max Expanded Octets

Haley Fredricks 1B wrote:Technically, yes, but in reality it more has to do with the formal charge. Whatever makes it the lowest is how many the octet should be expanded to.


I completely forgot about that. Thank you!
by Reina Robles 1H
Sun Nov 03, 2019 2:49 pm
Forum: Octet Exceptions
Topic: Max Expanded Octets
Replies: 2
Views: 20

Max Expanded Octets

For atoms with expanded octets, the amount they can expand to is limited to what shell they're in, right?

For example, Si has valence electrons in the 3p shell and can expand to fill the 3d shell but not beyond that.
by Reina Robles 1H
Sun Nov 03, 2019 2:35 pm
Forum: General Science Questions
Topic: Finding Formulas from Chemical Name
Replies: 4
Views: 53

Finding Formulas from Chemical Name

On the midterm, would we have to know how to write the molecular formula if we're given the chemical name? If so, how can I do that?

Thanks!
by Reina Robles 1H
Sun Nov 03, 2019 2:33 pm
Forum: General Science Questions
Topic: Study Tips
Replies: 13
Views: 129

Re: Study Tips

I definitely agree with all the advice here! Also, I talked to my TA about this, and he suggested using the Cornell note-taking system (although it might be too late to do that now). Here's a way you can do it if you don't know how to already: https://upload.wikimedia.org/wikipedia/commons/4/4f/Note...
by Reina Robles 1H
Fri Oct 25, 2019 8:59 am
Forum: Ionic & Covalent Bonds
Topic: Octet Rule Exceptions
Replies: 3
Views: 30

Re: Octet Rule Exceptions

They don’t need eight electrons to fill their shell. H and He only have the 1s shell, which only needs 2 electrons to fill it. Li and Be only have the 1s and 2s shell, and the 2s shell only needs two electrons to fill it.

Hope this helps!
by Reina Robles 1H
Tue Oct 22, 2019 3:31 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: HW 1E.5
Replies: 2
Views: 23

Re: HW 1E.5

In chemistry, penetration means an electron's probability density near the atom's nucleus. In other words, how close an electron can get to the nucleus. s-electrons of any shell can be close to the nucleus/have greater penetration, while the electrons of other subshells (p, d, etc.) have less penetr...
by Reina Robles 1H
Tue Oct 22, 2019 3:25 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: n,l,ml,and ms
Replies: 2
Views: 29

Re: n,l,ml,and ms

n is the shell, l is the subshell, ml is the orbital, and ms is the electron's spin. I hope this helps!
by Reina Robles 1H
Tue Oct 22, 2019 3:19 pm
Forum: General Science Questions
Topic: Units
Replies: 4
Views: 40

Re: Units

Velocity: meters per second Threshold energy: Joules Plank's constant: Joules times seconds Frequency: Hz (which is also cycles per second) You can also find these on the constants and equations sheet that they give us during tests: https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14A/c...
by Reina Robles 1H
Thu Oct 17, 2019 12:33 am
Forum: General Science Questions
Topic: Pre-Calc and Calculus
Replies: 3
Views: 38

Pre-Calc and Calculus

I didn't take calculus in high school and I don't remember a lot from pre-calculus, is there anything I should review/learn about for this class? Thanks!
by Reina Robles 1H
Wed Oct 16, 2019 8:34 pm
Forum: DeBroglie Equation
Topic: De Broglie Wavelength
Replies: 7
Views: 49

Re: De Broglie Wavelength

The De Broglie wavelength equation is used to see if a moving particle has detectable wavelike properties.
by Reina Robles 1H
Wed Oct 16, 2019 1:37 pm
Forum: Properties of Electrons
Topic: Intensity vs. Energy
Replies: 10
Views: 70

Re: Intensity vs. Energy

In the photoelectric experiment, increasing the intensity would only increase the number of photons (like making a light brighter, for example). On the other hand, the researches needed to increase the energy of each individual photon. This is done by increasing the frequency of the EM wave.
by Reina Robles 1H
Wed Oct 16, 2019 1:31 pm
Forum: General Science Questions
Topic: Salt Water: Mixture or Compound?
Replies: 4
Views: 25

Salt Water: Mixture or Compound?

Is saltwater a mixture or a compound? From what I remember, the textbook says one thing while the internet says another. Thanks!
by Reina Robles 1H
Wed Oct 16, 2019 1:29 pm
Forum: Properties of Electrons
Topic: Orbitals and Lobes
Replies: 3
Views: 24

Orbitals and Lobes

Are orbitals the same as lobes? In the textbook and lecture an atom's structure is usually described as shell --> subshell --> orbital, but where do lobes fit into this? Thanks.
by Reina Robles 1H
Fri Oct 04, 2019 9:42 pm
Forum: General Science Questions
Topic: Subshells and Orbitals
Replies: 1
Views: 30

Subshells and Orbitals

I read that the number of subshells in an atom's shell corresponds to the principal quantum number, but is there a pattern to how many orbitals are in each subshell? Thanks!
by Reina Robles 1H
Fri Oct 04, 2019 9:33 pm
Forum: Administrative Questions and Class Announcements
Topic: Study Tips/Schedule
Replies: 4
Views: 56

Study Tips/Schedule

I never really self-studied before and was wondering if anyone could explain to me how they plan to study for this class/any study tips in general? Thanks!
by Reina Robles 1H
Fri Oct 04, 2019 9:23 pm
Forum: Administrative Questions and Class Announcements
Topic: Periodic Table on the Test
Replies: 7
Views: 75

Periodic Table on the Test

Hi, I'm not sure if this question has been answered already, but will we be able to bring our own copy of the periodic table to the test? Thanks.
by Reina Robles 1H
Thu Oct 03, 2019 12:47 pm
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student - Part II [ENDORSED]
Replies: 130
Views: 2918

Re: Advice from a Medical Student - Part II [ENDORSED]

Thank you for the advice! Best wishes in medical school and beyond.
by Reina Robles 1H
Thu Oct 03, 2019 12:42 pm
Forum: SI Units, Unit Conversions
Topic: SI units for exam
Replies: 6
Views: 55

Re: SI units for exam

Thanks for all the information everyone! Also I think this is the link for the SI info that was mentioned earlier:

https://lavelle.chem.ucla.edu/wp-conten ... OUT_SF.pdf

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